1. Field of the Invention
The present invention generally relates to door supporting hinges and more particularly an electric hinge having chases or passageways incorporated therein for receiving insulated electrical conductors so that such conductors may pass from the door jamb to the door to operate electric locks, monitor the position of the door, condition of the lock or to accomplish any other purpose in which electrical energy is required, with the hinge including a completely enclosed tubular collar defining a hollow hinge pin extending between and interconnecting the hinge barrels on each leaf of the hinge with the collar being completely enclosed and concealed, and protecting the wires from attack in the event the hinge leaves and barrels are pried apart.
2. Description of the Prior Art
Along with the development of electrically operated locks for releasably securing doors in closed position, it has been necessary to supply electrical energy to the locks. In addition, monitor circuits are provided to indicate the condition of certain components of the electric lock as well as the position of the door, so that such information can be made available at a remote location. The use of electric locks on security doors introduces the problem of attack on the electrical circuits by persons wishing to alter the condition of the electric lock or alter the signals provided by the monitor circuits. It, therefore, is desirable for the electrical conductors to not only be concealed, but also to be protected from attack. The provision of electrical circuits through the hinge is known. For example, U.S. Pat. No. 3,838,234, issued Sept. 24, 1974, discloses an arrangement for this purpose but in this construction, the hinge barrel is provided with slip ring and wiper contact assemblies for maintaining the circuit during pivotal movement of the hinge leaves. Other patents, such as U.S. Pat. No. 3,659,063, 3,715,537, and 3,803,375 disclose arrangements in which circuit completing and breaking contacts or switches are associated with the hinge leaves to either complete a circuit through the hinge or operate a switch in a circuit in response to pivotal movement of the leaves of the hinge. Previously known devices in which the electrical contacts, switches, or the like, are exposed to view are also subject to attack by persons desiring to render the contacts or switches inoperative or to modify the operation in a particular manner. Structures in which slip rings and wiper contacts are utilized are rather complicated and expensive to manufacture with such devices also being subject to wear and ineffectiveness of the relatively movable components, thereby requiring substantial maintenance and repair. Also, such devices are subject to attack when the hinge leaves and barrels are pried apart.